Electric-current controller.



H. W. LEONARD.

ELECTRIC CURRENT CONTROLLER.

APPLICATION nun Jun. 24, 1906.

Patented Oct. 7, 1913.

H. W. LEONARD.

ELECTRIC CURRENT CONTROLLER. APPLIGATION FILED MAR. 24, 1906.

Q 3 SHEETS-SHEET 2.

Patented Oct. 7, 1913.

E ll' Fonwmm H. W. LEONARD. ELECTRIC CURRENT CONTROLLER. APPLIOATION FILED MAR. 24, 1906.

Patented Oct. 7, 1913.

3 SHEETS-SHEET 3.

. M avmehtoz HARRY WARD ;I.EoNAn-n, or BRONXVILLE, NEW YORK.

ELEC'IBIC-CURRENI' CONTROLLER.

To dll "whom it may concern.

Be it known 'that I, HARRY WARD LEONARD, a. citizen of the United States, residing at Dronxv'ille, in the county of VVestchester lmd Stdte of New York, have invented certain new and useful Improvements in Electric-Current -'Controllers, of which the following is a full, clear, and exact specification.

My in-ventiol'i relates to the control of electric currents and is of particular importalnce with reference to the control of ci1r rents supplied toeledtricmotors.

' By any invention, the motor may be started automatically, or retarded automati- (rally, or the speed may he miton atically controlled and iii-each case the control is such its to give the most efficient operation, "and the action is dependent upon and conforms to changes in the condition of the motor, so that a safe, -reliab'le and gradim l control is secured.

,My i-m'cntion also comprises means for protecting the'device controiled from abnorma l current or no-voltage conditions.

Although 'my invention is particularly i mpm'tant with reference to the control of electric motors, it has other a-ppliczttions and it wi l l be understood that the scope of my invent-ion is limited only as indicated :by the n-mien'ded claims.

Various forms of self-starters and self-stoppers have 'been knowmhat -they all contain objectionable featln'es. For example, they ustial'ly embody a dash-pot, or equiva'lent device vshic'h acts to effect a slow movement of an armature resistance controlling device which would otherwise move too rapidly. 'Such a dash-pot reqnires delicute adjustment, is likely to get 'out oforder, is affected by dhanges in temperature and other varying conditions of practice and moreover does not allow of the variation of the a'rm'at'lii'e resistance in the most desirable manner and in accord with the condition of the motor. Also the movement of the armatme resistance controlling device against the action of the dash-pot is generally due to the magnetic pnll developed by an electromagnet, but this actuating force is not of the proper amount to secure the 'best results under all conditions. Again, the electroma'gnet or its equivalent, acts against gravi t-y or a spring, not only during the starting up of the motor, but also alter the motor 18 Specification ot Iiet ters'Patent. Application flledlaroh 24, 1906. Serial 'NO. 3673881.

PatentedOct. 7,1913.

operating at full speed, thus requiring considerable energy for energi'Zin-gthe 'co'ihdurmg running conditions of the motor. Another cbj'ection is 'thhit 'no provision of simple, 'reliable and eflicient devices is "made for the prdtec't-ion "of the motor in circuits against improper conditions suo'h as novoltage and overload current. -Also the selfstoppers the motor from full speed retard the Ihdto'r to rest, &0 not e'fl'ect is not made dependent upon the speed a-nd mass of'the moving load.

my invention, these objections are overcome as Well as some other objections of various 'for'ins of 'prior apparatu My invention will be understood by the following description and the accompanying drawings, in whicl1 Figure 1-, is a diagram embodying one form of my invention and embodies an automatic starting device for a motor With nov'oltage and overload prdtedtion'; Fig. 2, is a modification of Fig. 1; Fig. 8, is a diagram ofnppa-ratu's which includes automatic field control in addition to the a-pparatu's of Fig. 1; Fig. 4 is a 'diagrarnsimilar to Fig. 3, except that the means for controlling the field is modified; Fig. 5, is a simi'lar'dia am with another inodi'fication for con'tro i l ing the field; Fig. 6, is a similar diagram With still another modification for field control; and Fig. 7 is a diagram of apparatus and connections with developmentof controlling switch for securing automatic starting, auto-- matic stopping and automatic reversing of the motor cont-rolled. I

Re fe'nin-g to Fig. 1, the armature of the motor to be controlled is indicated at 1, and the shunt field Winding for the motor is indicated at '2. The motor is shown as having a series field Winding 2. The two mains from the source of energy is indicated at 3, 4. In series with one of the mains is a coii 5 which carries the total current in circu-it, and upon the flow of an excessive current, its core will be raised and open switch 6. This switch is in series with a no-voltage coil 7, or coil for protecting the apparatus upon the occurrence of abnormally low voltage: This coil 7 and switch 6 are in series with a resistance 8, and connected across the mains 3, 4:. The strength of current thro'i'igh this coil is not 'suii'ic'ient to raise its core 9 from for automatically retarding v in a manner such as 'to secure the best result, because the braking its lowest position, but is sufficient to maintain the core in its upper position under normal conditions, after the core has been raised by other means. Movement of core 9 controls a switch 10 which is in the circuit of the armature 1, and when closed connects the armature across the supply mains. The core 9 and switch 10 are adjustably fixed upon the rod 11 which projects intothe path of the core or plunger 12 of the solenoid coil 13. The plunger 12 carries a rod 14 and by its movement controls the positions of a series of weights 15, 16 and 17. The rod 14 passes freely through the weights 15, 16, 17, and when the core is in its uppermost position, all of the weights rest one on the other and are held by the nut 18 which may be adj ustable on the rod. When the core or plunger is in its lowest position as shown, the weights are supported by fixed contacts and the plunger is supported by the upper wei ht 15 by means of the adjustable nut 19. Eac of the three weights serves as, or carries a switch, and when in their lowest position as shown, they serve to electrically connect the contacts upon which each rests; that is, 15 electrically connects contacts 20, 21,

' weight 16 electrically connects contacts 22,

armature 1 to contact 23, and weight 17 electrically connects contacts 24, 25. Between contacts 20, 21 is connected a resistance section 26, between contacts 22, 23 is connected a resistance section 27, and between contacts 24, 25 is connected a resistance section 28. Contacts 20, 22 are electrically connected, and contacts 23, 25 are also electrically connected. Contact 24 is connected to one terminal of armature 1, and contact 21 is connected to a terminal of switch 10. It will be seen that when switch 10 is closed, and all the weights or switches 15, 16, 17 are down, that the circuit through the armature will be from main 4, through 24, switch 17 contacts 25, 23, switch 16, contacts 22, 20, switch 15, contact 21, and then through switch 10 to the other side of the line. It will also be seen that when all the switches or weights 15, 16, 17 are raised by the upward movement of plunger 12, the resistances 26, 27, 28 are inserted in series with the motor armature. The switches 15, 16, 17 therefore act as short circuiting switches for the resistance sections 26, 27 28 respectively. 4

The coil 13 of the plunger 12, is connected from one side of the line, main 3, through a resistance 29 to a point 30 between one motor armature terminal and the armature starting resistance. The resistance 29 may be shunted by closing a switch 31 which may be in the. form. of a push button switch. In series with the field winding 2 of the motor is a variable resistance 32, and they form a circuit across the line when switch 10 is closed.

In Fig. 1, the parts are shown in the poand the plunger sition they occupy before order to start, the operator simply closes switch 31 for a moment. This forms a comparatively low resistance circuit from one side of the line through the solenoid coil 13 and through the motor armature to the other side of the line. As the motor is at rest, the potential of point 30 is substantially that of main 4, and the current which flows through coil 13 .is suiiicient to raise plunger 12 from its downward position. When this plunger moves upwardly it first raises the switch 17,

and causes switch 10 to be closed. This switch is therefore closed only after all the starting resistance has been placed in circuit. The closing of switch 10 completes the motor armature and motor field circuits across the line and themotor starts.

\Vhen the operator releases switch 31, after plunger 12 has moved to its raised position, the resistance 29is placed in circuit with coil 13, but the current which passes at that time is suflicient to maintain the plunger in its raised position. Also, after switch 10 is closed by the plunger, the current in coil 7 is sufficient to maintain the switch 10 closed as previously referred to. the motor gradually increases in speed, the counter-electromotive force of the motor gradually increases, causing an increasing difference of potential between point 30 and line 4, and a decreasing difference of potential between mm 30 and line 3; that is, the strength oi current in coil 13 depends upon the difference between the line electromotive force and the electromotive force of the motor armature. As the motor sp'eeds up, and causes this difference to gradually become less, the plunger 12 will, when its weight exceeds the magnetic pull, begin to fall until switch 15 engages contacts 20, 21, when the downward movement of the plunger will be checked temporarily by the automatic reduction of the weight of the falling mass. This engagement of switch 15 with its contacts, cuts out the largest resistance section 26 from the armature circuit and so permits the motor armature to further increase its speed. This further increase in speed causes the current in coil 13 to become less as above explained, 12 continues its downward movement until switch 16 engages its contacts 22, 23. This checks the fall of the starting up. In i then the switch 16, a then switch 15, after which it engages rod 11 Now as plunger on account of the reduction in mass has been stopped.

' 3ustment may under running and it together 28, and all of the armature resistance will then be out of circuit and full speed 'ilt? tained. It will 'be seen that in this automatic control, 'the various starting resistance sections, are'removed from circuit only when the. speed and counter volts of the motor armature is increased to such tent as to safely permit cutting out an atlditiona] resistance section. This insures safe starting of the motor without undue strains and without excessive currents-flowing. .Also thecomplete action of-starting up is made as rapidly-as possible consistent with protection of the motor and circuits. At full speed of the motor, the potential or point 30 is substantially that of line 3 which it has gradually approached as the speed of the motor increased. Therefore conditions, no current flows in coil 13 and no energy is-consumed by it. Also under running conditions, the plunger 12 is necessarily in its lowest position, with theswitches 15, 16, 17 are supporte by fixed parts. If no-volt age or abnormally low voltage occurs, coil I 7 will release its core 9, causing switch 10 to be opened, which will interrupt the motor armature and field circuits and stop fthe motor. On the other hand, if excessive current flows in the circuitthrough coil 5, its core will be raised and open switch 6, and by thus interrupting-the circuit of coil 7, the core 9 will he caused-to fal-land-switch 10 opened, which-will-also cause the motor to be brought :to rest. The motor can again be started only by the operator, and by closingswitch 31 temporarily. The insertion of Lthe resistance 29 in the circuit of coil 13 at all times except when switch 31 is closed, prevents any damage to the motor by excessive flow of-current after the motor For example, if during running conditions no-voltage should occur and cause the motor to stop as above explained. then in case the electromotive force of the line is restored, the motor will not he started except by closing switch 31 by the operator, owing to the fact that the current thmugh coil 13 and resistance 29 will be insufficient to cause plunger 12 to he. rniserh In the circuit of the no-voltage protective coil 7, I have indicated a push button switch 33 which may be located at any convenient location. By pressing this i switch the circuit of coil 7 is interrupted and the motor stopped. Of course any munher of such switches may be inserted in. the circuit of the no-voltage coil and located at desirable points of control. I Itwill be understood that any desired number of resistance steps or sect-ions may be used for controlling the motor or translating device; also that various means of adbe employed for securing-the of the controlling device, such best operation mg the motor, the controlling switch for this purpose is in the circuit of the novoltage .coil -7. This switch is designated the reference character-31, and a resistance shunted by this 'switch is designated by the character 29'. In the circuit of coil 13, is an automatic switch 34 normally held=o but adapted tobe closed when current ows through coil 7, being then attracted by its core. In order to -sta-rt,;switch '31. is closed,

and the current which then flows through coil? is sufiicient to cause the closure of switch 34, "but is not su-flicient-to raise core or'arma-ture '9, or to close switch 10. The closure of switch 34;, however, completes =the circuit across the line through coil 13 and the motor armature which causes plunger 12 to be raised as explained with reference to Fig. 1. Plunger '12 then closes switch 10 and the motor starts with all the armature resistance in circuit. As the motor speeds up and the current through coil 13 isgradual-ly decreased, the plunger will ran and control the increasein motor speed as before explained. Upon 't heoccurrence of any ahnormal-condition which interrupts theJfiow of current through coilv 7, switches 10 and 34 will "be opened and motor stopped. The motor cannot be again started until switch 31" is closed by the operator, leecause the current which may pass through coil 7 and resistance 29 is not ofsuiiicient-strength to cause switch '34 tobec'losed.

In Fig. 3, the construction and mode of operation is-simi-lar to that of Fig. 1, except that there is combined therewith automatic means for the control of the motor field strength for further control of the motor speed; In'ser-ies with the field Winding 2 of the motor, are sections 35, 36 of resistance, and these sections are controlled respectively by switches-37, 38 and which short circuit these sections when they are in their downward position, as shown. The switches 37, 38 are controlled by a plunger or core 39 in a manner similar to that in which core 12 controls its switches. The coil 40 for controlling the core 39 is-connected across the terminals of a resistance 41 of a material having a high coefficient 'of resistance such as nickel. In series with the resistance 41 across the line is a second resistance 4.2, a switch 43 carried by rod 14 and controlled by movement of the core 12 and switch 10. The switch merely -'serves to close the ias raised. The continued perature coefficient of resistance, such as German silver, or a material having a negative coefiicient. h

In starting, the plungers 12 and 39 are in their downward positions, as shown, and when the operator closes switch 31, the plunger 12 is raised and the motor is gradually brought up to speed by the falling. of the plunger as previously explained. Upon cutting out the last armature resist-ance step 28 by the switch 17, or soon after cutting it out, the switch 43 will be closed, causing current to flow across the-line through resistances 41, 42, the switch 10 having been closed by the upward movement of core 12. As the resistance 41, when cold, is comparatively small, the drop in electromotive force on this resistance will be comparatively low and, consequently, the drop in electromotive force on resistance 42 will be comparatively great. The coil 40 is therefore at first subjected to a low electromotive force which is not sufficient to cause the core 39, to be flow of current through the resistance 41, however, soon causes its resistance to be increased causing a greater drop in electromotive force to occur upon this resistance, and, consequently, subjecting coll 40 to an increased electromotive force. This will now be sufficient to raise core 39 and cause it to engage with and thereby raise switch 38 from its contacts. This causes resistance section 36 to be placed in series with the field winding 2, which reduces the strength of the field current and by thus weakening the field of the motor, results in an increase of the speed of the motor. The continued flow of current through resistance 41 further increases its temperature and resistance and so causes an increasing current to flow through coil 40, and when this current has become of suflicient strength, the core 39 will engage with and raise switch 37 and insert another resistance section 35 in the field circuit, giving increased motor speed. Similarly, additional steps of field resistancemay be controlled by the core 39. It will therefore be seen that with this construction and arrangement, the control of the field strength is made automatic, as well as the control of the armature resistance, and that it all results in proper sequence and manner of operation merely from closing switch 31 by the operator.

In Fig. 4, the arrangement is similar to that of Fig. 3, exceptthat the field resistance of the motor is controlled differently. In this construction, the field resistance sections 44, 45,. 46 are controlled by switches each having their separate core and individual controlling coils 47, 48, 49 respectively. These coils are connected in series with each other, but are graduated in strength so that coil 47 will be the first to raise its core and place resistance 44 in series with the field winding, then upon an increased current coil ,48 will raise its core and place resistance 45 in circuit, and upon a further increase in current, coil 49 will raise its core and place the resistance 46 in circuit. The number of turns in these different coils are shown graduated to secure this successive action, but it will be understood that other arrangements may be used for accomplishing the same purpose, such as making the cores of different weights, or varying the relative positions of the coils or of the cores. These controlling coils are in serles with a resistance 42 ,of low or no temperature coefficient of re-- and with a resistance 50 of high coefiicient of resistance, such as carbon, and the circuit across the line is completed by the switch 43 controlled by the plunger 12 and switch 10, as explained with reference to Fig. 3.

\Vith the construction of Fig. 4,

sistance, negative when .all the armature resistance is cut out of circuit and the switch 43 is closed, current will then flow across the line through switch 10, resistance 50, switch 43, coils 47,48, 49, and resistance 42. As the resistance 50 cold will have a comparatively high value, only a small current will flow, but as the carbon resistance 50 becomes heated the increased current will be sufficient to cause coil 47 to raise its core, and resistance section 44 will be inserted in the field circuit and increase the motor speed. Further heating of the resistance 50 causes an increased current to flow and coil 48 will next raise its core and .resistance section 45 will be insertedin the field circuit of the motor. Similarly, when the current strength has increased sufiiciently, due to the decreased resistance of 50, the coil 49 will raise its core and insert the final resistance section46 in the field circuit.

In Fig. 5, the resistance sections 44, 45,

46, of the field circuit are controlled by switches having compound wound controlling coils. The coils 47, 48, 49, are graduated as explained with reference to Fig. 4, and in this instance, are in series with a resistance 42 of substantially constant temperature coeflicient of resistance across the line through switches 10 and 43. In addition to these coils is an opposing coil 51 for each of the coils 47, 48, 49. The coils 51 are connected in series with each other and also in series with a resistance 41 of high temperature coefficient of resistance, and connected across the line through switches 10 and 43.

It will be understood that after all the armature resistance is cut out of circuit and .ance step r genera the switch 43 closed, current willflow across the hue through resistance 42, and coils 47-, 48, 49;'current will also flow across the hue through resistance 11 and coils 51. The strength of current which at first passes through the op coils 51 is comparatively large because the resistance 41 is cold comparatively low. As the resistance 41 lncreases in value by the heating e-fiectof the current, the current in coils 51 becomes less and their opposing efiect is decreased. Consequently, the coil 47 being the stronger will first raise its switch and insert resistance 44.- inthe field circuit. As .the current in coils 5-1 is further reduced, the resultant effect of coil 48. and its coil 51 will be suficient to next raise their core and insert resistance section 4.5 in the field circuit. As the resistance 41 becomes still higher, the strength of coil 49 will overpower that of its coil 51 at a predetermined condition of current, and the final resistwill be inserted in the field circuit, giving full speed of the motor. In

. stead of using a resistance 42 of constant temperature cocfiicient of resistance,- I may use in 1ts place a reslstance 'of negative tern,- pcrature coefhcient of resistance such as carbon. 'ith this substitution, the current through coils 47, 48, 49 will gradually in I crease, while the current in coils 51 is gradually decreased. There is thus secured an additional range of variation in magnetic strength for the control of the automatic switches.

In Fig. 6, the time element for securing gradual change of the field strength of the motor is a daslrpot and electromagnetic winding, and this is combined with other features of my invention. The field resistance sections 35,36, 36', are controlled respectively by switches 37, 38, 38, and these are successively controlled by the movement of plunger 3'9, as explained with reference to Fig. 3. The coil 40 for controlling core 39 is connected across the line through the switches 10 and 43. Secured to the plunger 39 is a rod carrying the piston 52 of the dashpot The dasl1-pot is arranged so that its upward movement is cushioned and can therefore only be slow, whereas its downward movement by means of relief valves in the piston is very rapid. After the armature resistance has been cut out of circuit, the field control .is commenced by the closing of switch 43. The current which flows, immediately begins to raise plunger 39, and during the slow upward movement successively lifts the switches 38', 38, 37 and inserts resistance sections 36, 36, 35, respectively.

In Fig. 7, the construction and connectic-11s are generally the same as that of Fig. 1,

as indicated by the use of the same reference Automatic starting of the motor in a forward direction is secured by moving the controlling switch so that contacts on line a successively make contact on lines I), 0, d. Positions 1) andc, are passed through in turning the controlling switch to the running position d. In position 6, connection is made from main 3, through drum contacts to contact '54, armature 1, coil 13, resistance 29, contact 55, through drum cont-acts to main 4. Contact 56 which is connected to a terminal of switch 10, is also connected to main 4: through the drum contacts. As the current through coil 13 and resistance 29 is not sufficient to raise core 12, the switch 10 will remain open and the motor does not start. In position a, current passesfrom Ina-in 3, through switch contacts to contact 57, switches 33 and 6, coil 7 r and resistance 8 to line 4. Coil '7 is therefore excited and ready to hold switch 10 closed when the same is raised by core 12. Current also now passes from main 3 to contact- 54:, motorarmaturel, coil 13 to contact 58-, through switch contacts to main 4. As the resistance 29 is now short circuited, the current in coil 13 will be suflicientto raise core 12, inserting armature starting resistances 26, 27, 28 and closing switch 10. The main motor armature circuit will thereby be closed across the lineand asthe shunt field winding is independently connected across mains 3, 4 the motor will start, say in a forward direction. The series field winding 2 of the motor is connected in main at separately from I the motor armature, so as always to receive current in the same direction regardless of the direction of current through the motor armature. As the motor speeds up and its counter-electromotive force increases, the core 12 will fall and gradually cut out sections of the armature resistance as before explained, bringing the motor up tospeed automatically.

It will be seen that the main motor circuit in starting is closed with a quick action at switch 10 apart from the hand controlled switch, so that sparking which might result in slowly or partially closing contacts Whichcarry large current at the manually operated switch is avoided. Also, in movmg the drum switch back toward 01f position in stopping, the interruption of the main current will occur at switch 10, which quickly 1 strength in this I cally,

opens, and which may if necessary be specially constructed to avoid detrimental effects of arcing. Thus in turning back from position 0 to 12, current through coil 7 will be interrupted between contact 57 and a switch contact, deenergizing coil 7 and causing switch 10 to be opened before the main contacts are broken at the manually operated switch. Also before the current through coil 13 is interrupted, the resistance 29 is inserted in circuit which reduces the current coil and so reduces the arcing at the manual switch.

In order to retard the motor automatithe controlling switch is turned so that contact is made on line g, passing through the intermediate positions 6, f

At e, the motor armature is closed through coil 13 and resistance 29, but the current flow is not sufiicient to raise core 12. In position f, resistance 29 is short circuited, and the armature rotating in the'field created by winding 2, generates current which raises core 12 inserting the armature resistance, and closes switch 10. In this position, coil 7 is also excited and holds switch 10 closed. The closing of switch 10, places the arma ture on a closed circuit through the starting resistance as follows :from motor armature 1, through contacts to contact 54, back to armature 1. In position 9, the connections are the same except that resistance 29 is in circuit with coil 13. The current passing in the closed armature circuit due to the motor armature now acting as a generator, places a heavy load on the motor causing it to rapidly decrease in speed and generate less electromotive force. As the circuit of coil 13 is subject to the electromot-ive force of the armature, being connected across its terminals, the decreasing electromotive force of the armature will weaken the magnetic strength of coil 13 and the core 12 will gradually fall. When switch 15 short circuits resistance section 26 by reason of the falling of core 12, the resistance of the local armature circuit is reduced and the retarding efiect is correspondingly increased. The motor therefore continues to rapidly decrease in speed and the falling of the plunger causes the resistance of the local circuit to be further reduced. This action continues until all resisttance is out out and the motor brought to res v For starting the motor in the reverse direction, the controlling switch is moved so that the fixed contacts successively make engagement on line 71-, i, and The connections in these positions correspond respectively with those of positions I), 0 and d, and the mode of operation is similar, except that the direction of current passing through the motor armature circuit and through the cirthe starting resistance,. switch 10, contact 56, and through drum cuit of coil 13 is reversed. Since the direction of current in the field windings of the motor is not changed, the rotation of the motor will be reversed. The action in starting up is otherwise the same as that explained with reference to starting up in a forward direction. When it is desired to automatically retard the motor when running in the reverse direction, the drum switch will be turned back through positions 2' and h, interrupting the main current at switct 10, as before explained, and contact at the controlling switch'is then made successively on lines 6', f, and g. The retarding action in these positions is the same as that previously considered with reference to positions 6, f, and g, and need not again be considered.

Although I have shown no means for automatic field control in Fig. 7, it will be understood that any of the forms described with reference to Figs. 3, 4:, 5 and 6 may be combined therewith. Also the forms of the manually operated switch of Fig. 7 may differ considerably in different instances, and it may sometimes be desirable to include the series winding 2' of the motor field in the closed local loop when retarding the motor, and thus secure greater field strength. I have not shown the details of construction of the manually operated switch, but it will be understood that these may conform to those in common use.

Although I have shown the motor controlled as being provided with a series field winding in each instance, the motor may be of other form than compound wound.

' It will be understood that my invention is capable of many applications, and is particularly advantageous incases where it is desired to attain the quickest possible starting and retarding of the load consistent with avoidance of excessive strains upon the apparatus, and with securing the comfort of passengers in case the invention is applied to the control of elevators, vehicles, train control, and so forth.

Although I have indicated various forms of my invention, it will be understood that many other modifications may be developed and still be within the scope of my invention.

Having thus described my invention, I declare that what. I claim and desire to secure by Letters Patent, is, r

1. The combination of an electric motor having a shunt field winding, electroqesponsive meansv comprising a movable element for controlling the current delivered to the armature of said motor, said elect-ro-responsive means being dependent upon the electrical action of said armature and responsive to a change in current difl'erent as regards strength of current from that carried by said armature and connected to cause itself to be automatically denergized by movement of said element, a switch for clos ingthe circuit of said elcctro-responsive means, a switch for closing the main circuit of said motor armature and for also closing the circuit of said shunt field winding, and mechanical means relating said last named switch to said elect-ro-responsive means for causing movement of said last named switchto be dependent upon the movement of'themovable element of said electro-responsive meansi 2. The combination of a motor having an armature winding and a shunt field Winding, an electro-responsive device, means for energizing sa i'd electro-responsive device by current differentas regards strength of cur-- rent from that passing through said illllliliture winding and dependent upon the electrical action of said armature, a switch for closing the main circuit of said armature winding and for closing the circuit of said shunt field winding, mechanical means relating said switch to said electro-responsive device for causing movement of said switch to be dependent upon movement of said electro-responsive device; and means whereby said electr0-responsive device controls a current supplied to said armature winding and automatically deenergizes itself.

3. The combination of a. motor having an armature winding and a shunt field winding, a source of electromotive force, electromagnetic means for controlling the current delivered to said armature winding'comprising means for applying the electromotive force of said source to said electromagnetic means and for causing said electromagnetic means to carry acurrent difierent as regards current strength from that carried by said armature winding and dependent upon the electrical action of said armature winding and for automatically reducing the electromotive force applied to said electroinagnetic means, a switch for closing the main circuit of said motor including the circuit of said shunt field winding, and mechanical means relating said switch tosaid electromagnetic means for causing move-- ment of said switch to be dependent upon movement of said electromagnetic means.

4. The combinationcf a source of electromc-tive force, an electric motor, an electroresponsive controlling device, means for connecting said device in series with the armatureof said motor across said source for controlling acceleration of the motor, and means for connecting said device with the armature of said motor for controlling the retardation of the motor.

The combination of a source of electromotive force, an electric motor, an electroresponsive controlling device, means for connecting said device inseries with the armature of said. motor across said source for having an automatically controlling-the motor acceleration, and means for connecting said device with the motor armature for controlw ling themotor during retardation.

6. The combination. of an electric motor, a; singrle electromagnetic controlling'winding, and means for causing said: winding to; automatically control the acceleration and retardation of said motor by controlling the" electric energy employed? to ellect such acceleration and retardation.

7 The combination of an electric: motor :hav1ngf an armature winding and: a shunt field winding, an e-lectrmmesponsrve device'- conneoted therewith,v sand device being nesponsive to a current different asregards current strength from: that carried by the motor armature and dependent upon theelectrical action of said a mature; means for gradually reducing the electromotive force'- u-ponsaid device and increasing the electrm motive force applied. to the; motor armature: and thereby accelerate saidmotor, a. switclr for closing the main ei-rcuit'of said motor including the circuit of said field winding, and mechanical means 1 to said device for causing movement of said relating said switch switch to be dependent upon movement of said device: v

8. The combination of an electric; motor armature and a shunt fieldwind-- ing, an electro-responsive device connected therewith, said device being responsive to the -electr'omotive force upon the motor armature, means for gradually and automatically reducing the electromotive force upon said device and increasing the electro motive force applied to the motor armature and thereby automatically accelerate said motor, a switch for closing the main-circuit of said motor including the circuit of sai d field winding, and mechanical means relating said switch to said device for causing movement of said switch to be dependent upon movement of said device.

9. The: combination of an electric motor having an arrn'atu're winding and a; shunt field winding, arr-electro-responsiw controlling device dependent upon the result and. eflect of gravity and-magnetism, means for accelerating saidmotor by decreasing the magnetic etlect. said device being responsive to a change in current different as regards strength of current from that carried by the motor armature, a switch for closing the main circuit of said motor including the circuit of said field Winding, and mechanical means relating said switch to said device for causing movement -of said switch to be dependent upon movement of said device.

10. The combination of a motor having an armature wind-ting andas shunt winding, acon-trolling device therefor comprising a single electro responsi-ve winding and a series of independently movable IBI O cluding the circuit of said field winding,

and mechanical means relating said switch to said device for causing movement of said switch to be dependent upon movement of said device.

11. The combination of avsource of electromotive force, an electric motor having an armature winding and a shunt field winding, electromagnetic means dependent upon the difierence between the electromotive force of said source and the counter electromotive force of said motor for automatically accelerating said motor, said means having a winding which carries a current different as regards current strength from that passing through the motor armature, a switch for closing the main circuit of said motor includin the circuit of said field winding, and mec anical means relating said switch to said electromagnetic means for causing movement of said switch to be dependent upon movement of said electromagnetic means.

12. The combination of a source of electromotive force, an electric motor having an armature winding and a shunt field winding, a main switch adapted to close the main circuit of said armature winding and also the circuit of said field winding, a resistance controlling movable element, an electromagnetic winding for controlling said switch and said element, said winding being connected in circuit to cause the current through it to be dependent upon the counter volts of the motor armature, causing said winding to automatically deenergize itself.

13. The combination, of an electric motor,

a controlling switch, a no-voltage coil for holding said switch closed, and automatic electromagnetic means for closing said switch, said means comprising a winding in series with the motor armature, said winding acting upon a movable element to effeet the closure of said switch.

14. The combination of an electric motor, a controlling switch, a no-v'oltage coil for holding said switch closed, and electromagnetic resistance controlling means for closing said switch automatically, said means comprising a winding in series with the armature of the motor, said winding acting upon a movable element to efiect the closure of said switch.

15. The combination of an electric motor, a main switch, armature resistance controlling switches, a field resistance controlling switch, and electromagnetic means for closing said main switch in its upward movement and said armature'resistance controland means for ling switches in its downward movement and finally said field resistance controlling switch.

16. T he'combination of an electric motor, a main switch, armature resistance controlling switches, a field resistance controlling switch, electromagnetic means for closing said'main switch inits upward movement and said armature resistance controlling switches in its downward movement, and

finally said field resistance controlling switch, and means for causing said action of said electromagnetic means to occur for accelerating, retarding and reversing said motor.

17. The method of starting an electric motor, which consists in subjecting a controlling device to the full electromotive force of the source, subjecting said device to the gradually decreasing difierence in electromotive 'force between said source and that of the counter electromotive force of the motor for controlling the acceleration of the motor, and subjecting said device to current'generated by the motor armature for controlling the retardation of the motor.

18. The method of controlling an electric motor which consists in passing a current from the source through a controlling device in series with the motor armature for controlling the reduction of resistance in series with the motor for accelerating the motor, and passing a current generated by the motor armature through said device for controlling the retardation of the motor.

19. The'method of controlling an electric motor, which consists in passing a current from a source through a controlling device for controlling the reduction of resistance in series with the motor armature for accelcrating the motor, and passing a current generated by the motor armature through said device for controlling the reduction of resistance in series with the motor armature for retarding thev motor.

20. The combination with an electric motor, of means for automatically accelerat ing the motor, said means comprising two functionally related automatically movable resistance controlling devices, one of said devices having an actuating winding in series with the motor armature, and each of said resistance controlling devices being adapted to vary its respective resistance gradually.

21. The combination with an electric motor, of two resistance controlling independently movable elements, one of said elements being in series with the motor armature and the other in series with the motor field winding, functionally related automatic means for automatically controlling said elements for accelerating the .ance in series wi causing the motor motor by gradually decreasing the resistth the motor armature and then gradually increasing the resistance in series with the said motor field winding, and means under control of the operator for -to be dynamically brought substantially to .-rest.

22. The combination ofan electric motor. .a field regulating resistance comprising a plurality of steps of resistance, electromesponsive means dependent upon the s edof the motor for automatically controlling. the .number of resistance steps. in. circuit, ,and a magnetic winding in series with. the motor armature and adapted to automatically-con- .trol the circuit ofsaid electro-responsive .means.

23. The combination of-an electric motor, .a plurality of automaticswitches for autovmatically controlling resistance in the motor armature circuit, a plurality of. automatic switches for automatically and cumulatively controlling resistance in the field circuit of the motor during acceleratlion of the inotor,.saicl latter. switches be-. ing dependent uponct-he antomaticmovement of said firs means controlled by the. operator for causing the motor armature to, generate-a braking current for retarding the motor.

24. The combination with an .electric -motor of apparatus for starting said motor comprising a manually closable.switch,-,an automatic switch for controlling the main circuit, an armature resista nce, .automatic means for reducingsai-d resistance,-means for controlling the opening of .said automatic switch upon the occurence of no. voltage. means for automatically varying the field strength of .the motor, .vsaid latter means being controlled by said automatic means for reducingv the armature resistance for protectively relatingsaid field arying and armature resistance varying means,.a-nd means for causing the .motor to generate a current for bral ng purposes.

The combination of an electric motor, two controlling resistances for said motor, two automatic electric means for controlling said resistances respectively during acceleration of the motor, one of said means having its circuit automatically controlled by the other of said means, and both otsaid means automatically and successively controlling a plurality ofsteps of resistance, and means controlled by theoperator for causing the motor armature to generate a current for dynamically braking the motor I armature. 1

26. The combination of-an. electric motor, a starting resistance, means for removing said resistance from thearmature circuit of the motor, a series of steps of resistance for controlling the field strength of the.

t named switches, and

motor,,,a ..seriesof independently. automatic- .ally;..moyable switches for controlling said steps respectively, and means for causing the operation of. said automatic switches to dynamically brake the-motor.

27. The combination of a circuitin which the current is tobe controlled,,and a time .limitQmeans-tor automatically varying the current in .said circuit comprising two, re- .-sistances having different temperature coefiicients inseries-with each other and an automatically movable responsive controlling element.

va constant electrornotive force-supply circuit,,and means forautomatically starting the-motor comprising a switch for controlling the armature circuit, an electrorespon- Sire device-having a. its action, said winding when energized causingsaid device to effect the closure of ..said switch and thereby start the motor, (said winding, being denergized during normal-operation of-:the.motor, and a second velectroresponsiye.winding for holding said .switch. clos d during normal operation of the-,motor and which releases said switch .upon .,t.he ..occ urrence of no-voltage, and means for causing said switch to be released .upon the. occurrence. of overload.

29. .The combination ofa translating de- ..vice, a switch for-controlling the main circuit,,an electroemagnetic winding foreifectging the closure of said switch, a second electro-magnetic winding for holding said switch closed,.- means,- for automatically de- -energizin g.t l1e closingv winding under nor- ;mal operating conditions, and means-for automatically deenergizing the holding wind- .undierv abnormal current conditions.

30. The combination of an electric motor .havinganarmature winding and ,a shunt ..field..winding, two windings for-controlling the operation of said motor, said two wind sings being-parallel witheach other rela- .twely to the constant electromotive force Isupplycircuit, meanscontrolled by one of said windings for automatically effecting the establishment .of the 'motor field .and armature currents for starting the motor, means for deenergizingsa-id winding, and .means controlled by the other of said windings for maintaining the circuit closed after said. first windingis denergized.

.31. The combination of an electric motor, an .arn1ature resistance therefor, automatic .means comprising a movable element adapted by its movement to reduce said armature resistance, means for automatically weakening the magnetic field of the motor bysuccessive changes of said magnetic field,.said latter means comprlslngan electro magnetic controllingcoil the circuit otwhich is controlled by. said element, and

winding for controlling 28. ,The combination of. an electric motor,

then autoi'natically and means under control of the operator for causing the automatic dynamic braking ot the motor.

32. The combination of an electric motor, an armature resistance, means for automatlrally and gradually increasing the voltage upon the motor armature terminals and for gradually weakening the magnetic field of the motor for accelerating the motor, said means comprising. a movabl element for controlling said armature resistance and field controlling means, said latter means having an electroresponsive device the circuit of which is automatically controlled by the movement of said element, and means under control of the operator for causing the automatic dynamic braking of the motor.

The combination of an electric motor, a supply circuit, and means for automatic'ally gradually varying the electromotive force upon the motor armature and for gradually varying the magnetic field strength of the motor for varying the motor speed comprising a main controlling winding in series with the motor armature across the supply circuit but energized by a current other than the actuating current of the motor armature. i

34. The combination of a constant electromotive force supply circuit, two devices in series with each other in a branch connected to said circuit and dividing the drop in electromotive force between them, and a controlling winding connected in circuit with one of said devices and in parallel with the other of said devices for controlling the relative drop of electromotive force on said devices.

35. The combination of a source of elec 1 tromotive force, an electric motor, an electro-responsive device forautomatically controlling the energy in the motor armature, and means for connecting said electroresponsive device in series with the motor armature and the source for controlling the motor armature during acceleration and for connecting said device and motor armature for controlling the motor armature during retardation. I

36. The combination of a source of electromotive force, an electromotive force producing device, and controlling means for said device comprisin a controlling winding and means for su jecting said winding to the difference between the electromotive force of the source and that of said device and for connecting said winding so as to be subjected to the electromotive force of said device.

37 The combination of two electromotive force producing devices connected in circuit so that the electromotive forces oppose each other, a controlling winding for controlling the electromotive force of one of said devices, and means for connecting said winding in series with said two devices or in series with only one of said devlces.

38. The combination of an electric motor, an automatically movable circuit controlllng element for controlling the armature circuit, anautomatically movable circuit controlling element for controlling the field circuit an controlled by said armature circuit controlling element, an automatically movable circuit controlling element for controlling both the armature circuit and field circuit, and means protectively functionally relating said elements.

39. The combination of atranslating device, a switch, a coil incapable of closing but adapted for retaining said switch in closed position and for releasing the switch and allowing it to open upon no-voltage, said coil being connected inparallel with said device,-

a resistance in series with said switch, and a coil for automatically controlling the closure of said switch and for automatically controlling said resistance.

40. The combination of an electric motor, an armature resistance controlling movable element, electromagnetic means for automatically moving said element for inserting the armature resistance, a motor field resistance controlling movable element, and electromagnetic means for automatically moving said element for inserting the field resistance.

41. The combination of an electric motor having a shunt field winding connected in a local closed circuit with-the motor armature, a switch, means for automatically closing said switch for energizing the armature and field circuits of the motor, and automatic electroresponsive means for accelerating the motor by first increasing the voltage across the armature and then weakening the magnetic field strength, the weakening of the field strength being automatically dependent upon the completion of the increase in voltage across the armature.

42. The combination of an electric motor having an armature winding and a shunt field winding, a switch for establishing the actuating current of said motor and also the current through said field winding and Ill for breaking the current on no-voltage, electro-responsive means dependent upon a change in the counter-electro-motive force of the motor for accelerating the motor, and mechanical means relating said electroresponsive means to said switch, whereby movement of said switch is dependent upon movement of said electro-responsive means.

43. The combination of an electric motor, a switch'for establishing the total actuating current of said motor, automatic means for automatically closing said switch for establishing said actuating current, and electro-responsive means mechanically func- 5 the motor armature and weakening the mo- In testimony whereof I a tionally related to said switch and respon is generating a braking current for retardsive toa change in the counter-electroinotive ing the motor, and a single Winding for force of the motor for accelerating the moautomatically varying said resistance durtor by increasing the electromotive force on ing acceleration and duriiliqg retardation.

X my signature, 15 tor field strength. v

44. The combination of an electric motor, a variable armature resistance for control- Witnesses: ling the armature curren While the motor is CAROLYN G. LEONARD, 10 being accelerated and also While the motor SARAH MCDONALD.

in presence of two Witnesses.

H. WARD LEONARD. 

